* Moved back from .net 4.5 to .net 4 as requirement
 * Added log4net to dependencies
 * Added System.Configuration to frameworkassemblies

Note that the library is also dependent on the Microsoft.WindowsAzure.ServiceRuntime and Microsoft.WindowsAzure.StorageClient libraries. However, the current nuget packages for these libraries appear to be mixed-mode, which is why I haven't included them as a dependency.